MC-13864: Consumer always read config from memory

design-documents/asynchronous-operations/poison-pill.md

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+## Glossary
+
+poison pill
+: message that added after list of events in Data Storage that signals that consumer should die.
+
+### Overview
+
+Right now our consumer depends on config/objects in-memory state. After application was bootstrapped it initialize a lot of object that are always kept in memory after first load - config, websites, etc.., since our consumers are long-living and their live time limited only by message count it could happens that our consumer keep outdated im-memory config/objects states. Considering that, we need to introduce the way to reinit them.
+
+### Design
+
+Basic implementation of how the pill will be added should be implemented inside Magento Framework. We will share the api that let each module call whenever it needed.
+
+Api Interface - *PoisonPillInterface* will be inside Magento Framework, implementation in MessageQueue module.
+
+PoisonPillInterface
+```php
+/**
+ * Put poison pill inside DB.
+ *
+ * @throws \Exception
+ * @return int
+ */
+public function put();
+```
+
+Before process new message, consumer will compare version of PoisonPill in-memory state with latest in DB. If version is different consumer dies and next cron:run will start new instance of consumer.
+
+#### Acceptance Criteria Fulfillment
+
+1. If consumer takes message to process after poison pill was placed, consumer must be reinited.
+
+#### Extension Points and Scenarios
+
+We will put poison pill into Data Storage based on common Magento extension points. 
+